So my GF has a nephew who is 12, and we were introduced a few days ago. His parents were concerned because he insisted on a pair of women's high heels, which he wears around their house. (I think they wanted me to try and talk him out of it, but instead I talked them into letting him explore this issue, to create a safe place for him to explore the
possibility that he may be trans)
We decided to just let the meet-n-greet just flow naturally, rather than bring anything up to him directly (being 12, he's probably a bit insecure about things), but fortunately he brought an issue up himself...asked his mom, "Is Beth a man...or a woman?"

So later we--his mom, my GF ("soft butch" lesbian) and I--went to talk to him. I said that he had a good question, and the answer was that I was born with a male body, but "inside" (pointing to my heart) I was a woman. And, that it was difficult for me to be a woman inside (taps on heart) but with a male body, so the doctors were helping me change my body's gender to be female.
I said this twice (the first time he was playing roughhouse on the bed--typical 12yo behavior LOL), but then he suddenly sat up straight and looking at his aunt (my GF) said, "That's just like you, (GF's name)...you're a girl, but sometimes you're like a guy!"
We all agreed, that was a good sign of understanding. After that, I was Beth, "she" and "her" the rest of the visit.
And since I am accepted by his mom, hopefully that will help him in his journey, wherever it may lead.